Tryptophan metabolite norharman secreted by cultivated Lactobacillus attenuates acute pancreatitis as an antagonist of histone deacetylases

Bacillus paralicheniformis-mediated gut microbiota promotes M2 macrophage polarization by inhibiting P38 MAPK signaling to alleviate necrotizing enterocolitis and apoptosis in mice

Clostridial necrotizing enterocolitis is a severe gastrointestinal disease induced by Clostridium, strongly associated with intestinal dysbiosis. Fecal microbiota transplantation (FMT) has proven effective in treating gastrointestinal diseases by remodeling intestinal microbial homeostasis. However, it remains unclear whether FMT from donors with beneficial microbiota can improve the recipient's intestinal function more efficiently. This study found that probiotic Bacillus paralicheniformis SN-6-mediated gut microbiota effectively prevent Clostridial necrotizing enteritis and explored the underlying molecular mechanisms. Data demonstrated that SN-6 altered gut microbiota composition, ameliorated Clostridium perfringens-induced intestinal microbiota dysbiosis and metabolic reprogramming, particularly enhancing tryptophan metabolism. This led to a marked reduction in intestinal barrier damage and inflammation. FMT from SN-6-treated mice reduced jejunal inflammation in Clostridium perfringens-infected mice, strengthened jejunal barrier and enriched beneficial bacteria, such as Lactobacillus, Blautia, Akkermansia. Furthermore, 3-indoleacetic acid (IAA), a metabolite enriched by SN-6, activated aryl hydrocarbon receptor (AhR), suppressed the P38 mitogen-activated protein kinase (P38 MAPK) signaling, and drove macrophage polarization from M0 to M2-type, thereby reducing apoptosis and excessive inflammation. This study highlights Bacillus paralicheniformis SN-6 as a key modulator of intestinal immunomodulation via the gut microbiota-IAA-AhR-P38 MAPK axis, offering a potential therapeutic target for preventing and controlling clostridial necrotizing enteritis.

Microbiota, mitochondria, and epigenetics in health and disease: converging pathways to solve the puzzle

Dysbiosis, which refers to an imbalance in the composition of the gut microbiome, has been associated with a range of metabolic disorders, including type 2 diabetes, obesity, and metabolic syndrome. Although the exact mechanisms connecting gut dysbiosis to these conditions are not fully understood, various lines of evidence strongly suggest a substantial role for the interaction between the gut microbiome, mitochondria, and epigenetics. Current studies suggest that the gut microbiome has the potential to affect mitochondrial function and biogenesis through the production of metabolites. A well-balanced microbiota plays a pivotal role in supporting normal mitochondrial and cellular functions by providing metabolites that are essential for mitochondrial bioenergetics and signaling pathways. Conversely, in the context of illnesses, an unbalanced microbiota can impact mitochondrial function, leading to increased aerobic glycolysis, reduced oxidative phosphorylation and fatty acid oxidation, alterations in mitochondrial membrane permeability, and heightened resistance to cellular apoptosis. Mitochondrial activity can also influence the composition and function of the gut microbiota. Because of the intricate interplay between nuclear and mitochondrial communication, the nuclear epigenome can regulate mitochondrial function, and conversely, mitochondria can produce metabolic signals that initiate epigenetic changes within the nucleus. Given the epigenetic modifications triggered by metabolic signals from mitochondria in response to stress or damage, targeting an imbalanced microbiota through interventions could offer a promising strategy to alleviate the epigenetic alterations arising from disrupted mitochondrial signaling.

Norharmane prevents muscle aging via activation of SKN-1/NRF2 stress response pathways

Sarcopenia, the age-related decline in muscle mass and function, is a significant contributor to increased frailty and mortality in the elderly. Currently, no FDA-approved treatment exists for sarcopenia. Here, we identified norharmane (NR), a β-carboline alkaloid, as a potential therapeutic agent for mitigating muscle aging. We aimed to determine the ability of NR to delay muscle aging in Caenorhabditis elegans (C. elegans), mouse, and muscle cells in mice and humans. NR treatment improved swimming ability and increased the maximum velocity in aged C. elegans. Transcriptomic analysis revealed that NR upregulated detoxification genes in C. elegans, including cytochrome P450, UGT, and GST enzymes. NR-induced benefits were dependent on the SKN-1/Nrf2 stress response pathway. In mammalian models, NR delayed cellular senescence in human skeletal muscle myoblasts and enhanced myogenesis in C2C12 cells and primary aged myoblasts. NR supplementation in aged mice prevented muscle loss, improved muscle function, and reduced markers of cellular senescence. We found that the p38 MAPK pathway mediated NR activation of Nrf2 by disrupting the Nrf2-Keap1 interaction. NR also improved oxygen consumption rates and promoted mitochondrial biogenesis. These findings suggest that NR is a promising candidate for preventing sarcopenia and improving muscle health.

Implications of Raftlin in different diseases: from molecular biology to diagnostic value

Raftlin (raft-linking) protein is an essential component of the lipid raft structure and plays a crucial role in B and T cell signaling pathways. It facilitates B cell receptor (BCR) signaling by promoting calcium mobilization and tyrosine phosphorylation in the cells while colocalizing with BCR on the cell membrane. Interestingly, Raftlin is internalized in lipopolysaccharide-stimulated T cells by colocalization with Toll-like receptor 4 (TLR4), wherein it exerts a similar role as in B cells. The protein also effectuates poly(I:C) internalization into TLR3-positive endosomes in dendritic and epithelial cells through clathrin binding, thereby affecting interferon-β production. In addition, Raftlin controls the vascular endothelial cells and participates in cell growth and proliferation. Recent studies have indicated Raftlin to be a novel biomarker for the diagnosis due to its upregulated expression in malignant diseases. In this integrated study, we present the biological functions of Raftlin and its expression to provide a theoretical basis for the prevention, diagnosis, and treatment of various diseases.

Updated review of research on the role of the gut microbiota and microbiota-derived metabolites in acute pancreatitis progression and inflammation-targeted therapy

Acute pancreatitis (AP) is characterized by autodigestion of the pancreas, and some patients may rapidly progress to systemic inflammation, pancreatic necrosis, and multi-organ failure. Numerous studies have detailed the bidirectional communication networks between the pancreas and the intestinal microbiota, as well as its metabolites. Such crosstalk affects the progression of AP and recovery through intestinal barrier disruption. Furthermore, advances in experimental research and clinical studies have indicated that gut microorganisms exhibit distinct alterations in response to different levels of severity and etiologies of AP. This information has greatly expanded our knowledge of the role of the gut microflora and microbial metabolites in the pathology of disease and has reinforced the basis of therapeutic approaches that target candidate intestinal microbiota. In this review, we aim to provide an overview of the composition and diversity of the gut microbial community, to highlight the candidate bacteria and microbiota-derived metabolites responsible for AP, and to elucidate their interactions with and regulation of immune-relevant receptors in intestinal epithelial cells (IECs) in the host. Future research should focus on identifying and characterizing AP-associated bacterial strains, elucidating their distinct pathogenic mechanisms across different etiologies and stages of AP, and leveraging these insights to develop preventive and therapeutic strategies.

Exploring similarities and differences in anti-atherosclerotic potential bioactives among Dendrobium species by UPLC-Q-Exactive Orbitrap MS

Atherosclerosis is a primary cause of cardiovascular disease, straining healthcare systems. Dendrobium officinale, a widely used food-medicine homology, has demonstrated anti-atherosclerotic (anti-AS) properties, with other species listed in pharmacopoeias exhibiting similar effects. However, their efficacy varies, and the impact of interspecies variations on compounds and mechanisms in Dendrobium's anti-AS effects remains unclear. This study aimed to explore the anti-AS compounds and mechanisms across various Dendrobium species. The chemical composition of D. fimbriatum, D. officinale, D. devonianum, D. gratiosissimum, and D. catenatum was analyzed using UPLC-Q-Exactive Orbitrap MS. Network pharmacology predicted the pharmacological basis and molecular mechanisms. Molecular docking experiments assessed the binding affinity of the identified compounds with target proteins. A total of 12 different and 65 common components were identified. Key therapeutic targets included SRC, STAT3, and PIK3CA, along with relevant signaling pathways linked to AS prevention. The study provides insights into interspecies differences in Dendrobium's anti-AS properties.

Lysine acetylation and its role in the pathophysiology of acute pancreatitis

Acute pancreatitis (AP) represents a severe inflammatory condition of the exocrine pancreas, precipitating systemic organ dysfunction and potential failure. The global prevalence of acute pancreatitis is on an ascending trajectory. The condition carries a significant mortality rate during acute episodes. This underscores the imperative to elucidate the etiopathogenic pathways of acute pancreatitis, enhance comprehension of the disease's intricacies, and identify precise molecular targets coupled with efficacious therapeutic interventions. The pathobiology of acute pancreatitis encompasses not only the ectopic activation of trypsinogen but also extends to disturbances in calcium homeostasis, mitochondrial impairment, autophagic disruption, and endoplasmic reticulum stress responses. Notably, the realm of epigenetic regulation has garnered extensive attention and rigorous investigation in acute pancreatitis research over recent years. One of these modifications, lysine acetylation, is a reversible post-translational modification of proteins that affects enzyme activity, DNA binding, and protein stability by changing the charge on lysine residues and altering protein structure. Numerous studies have revealed the importance of acetylation modification in acute pancreatitis, and that it is a favorable target for the design of new drugs for this disease. This review centers on lysine acetylation, examining the strides made in acute pancreatitis research with a focus on the contributory role of acetylomic alterations in the pathophysiological landscape of acute pancreatitis, thereby aiming to delineate novel therapeutic targets and advance the development of more efficacious treatment modalities.

Chidan Tuihuang granule modulates gut microbiota to influence NOD1/RIPK2 pathway in cholestatic liver injury recovery

BACKGROUND

Cholestatic liver injury (CLI), which occurs if bile acids are imbalanced and the liver becomes inflamed, is difficult to treat effectively OBJECTIVE: We investigated how the Chinese patent medicine Chidan Tuihuang granule (CDTH) ameliorates cholestatic liver injury with a focus on its effects on the NOD1/RIPK2 pathway and intestinal flora METHODS: We used an ANIT-induced SD rat model of CLI to evaluate the therapeutic effects of CDTH. The experimental design included control, model, UDCA (ursodeoxycholic acid) and CDTH treatment groups. UHPLC-Q-Orbitrap-HRMS was used to analyse the blood components of CDTH. The efficacy of CDTH was assessed by liver function tests, histopathological examination (HE and TUNEL staining), transmission electron microscopy, and ELISA to measure apoptosis and inflammatory markers. Mechanistic insights were obtained using transcriptomics and RT-qPCR, while alterations in the expression of key proteins were studied using western blotting, immunohistochemistry, and immunofluorescence. Furthermore, the impact of CDTH on the gut microbiota and its associated metabolite, meso-2,6-diaminopimelic acid (DAP), which is linked to NOD1 activation, was examined and confirmed through in vitro RESULTS: The experimental results demonstrated a notable elevation in serum levels of AST, ALT, ALP, TBA, TBIL, and DBIL in the rats belonging to the model group, accompanied by the infiltration of inflammatory cells, hepatocyte degeneration, and necrosis in the liver tissue. CDTH administration significantly improved liver function and cholestasis indicators. Transmission electron microscopy and TUNEL staining revealed a marked reduction in liver cell apoptosis with CDTH treatment. ELISA results showed that CDTH effectively reduced inflammatory markers. Transcriptomic analysis showed that CDTH inhibited the NOD1/RIPK2 pathway, resulting in a significant decrease in the expression of NOD1, RIPK2 and associated genes in liver tissue. Gut microbiota analysis demonstrated that CDTH regulated intestinal flora structure, reducing the abundance of DAP-producing Gram-negative bacteria such as lactobacilli. In vitro experiments confirmed that CDTH enhanced cell viability by downregulating the DAP-mediated NOD1/RIPK2 signaling pathway secreted by intestinal bacteria CONCLUSION: CDTH ameliorated liver damage in cholestatic rats by inhibiting the NOD1/RIPK2 signaling pathway through regulation of gut flora and downregulation of DAP metabolites.

Mechanisms of intestinal injury in polychaete Perinereis aibuhitensis caused by low-concentration fluorene pollution: Microbiome and metabonomic analyses

The polychaete Perinereis aibuhitensis is used for bioremediation; however, its ability to remove fluorene, a common environmental pollutant, from sediments remains unclear, especially at low concentrations of fluorene (10 mg/kg). In this study, we explored the mechanism of intestinal injury induced by low concentrations of fluorene and the reason intestinal injury is alleviated in high fluorene concentration groups (100 and 1000 mg/kg) using histology, ecological biomarkers, gut microbiome, and metabolic response analyses. The results show that P. aibuhitensis showed high tolerance to fluorene in sediments, with clearance rates ranging 25-50 %. However, the remediation effect at low fluorene concentrations (10 mg/kg) was poor. This is attributed to promoting the growth of harmful microorganisms such as Microvirga, which can cause metabolic disorders, intestinal flora imbalances, and the generation of harmful substances such as 2-hydroxyfluorene. These can result in severe intestinal injury in P. aibuhitensis, reducing its fluorene clearance rate. However, high fluorene concentrations (100 and 1000 mg/kg) may promote the growth of beneficial microorganisms such as Faecalibacterium, which can replace the dominant harmful microorganisms and improve metabolism to reverse the intestinal injury caused by low fluorene concentrations, ultimately restoring the fluorene-removal ability of P. aibuhitensis. This study demonstrates an effective method for evaluating the potential ecological risks of fluorene pollution in marine sediments and provides guidance for using P. aibuhitensis for remediation.

Effects and mechanisms of using "clean" smoke particles in the smoking process on the formation of β-carboline heterocyclic amines (β-CHAs) in smoked meat patties

β-Carboline heterocyclic amines (β-CHAs), known for their synergistic neurotoxic and carcinogenic effects, are predominantly produced by humans through cigarette smoke and food and are found particularly in meats cooked at high temperatures. Few studies have explored the differences in the mechanisms of accumulation of β-CHAs in smoked meat and meat processed at high temperatures. In this research, the concentration of β-CHAs in smoked meats prepared using a variety of wood materials was measured using LCMS/MS. Additionally, key volatile organic compound markers associated with β-CHAs accumulation in smoke were identified through GCMS and multivariate statistical analysis and subsequently confirmed in a chemical simulation system. Three types of strainers, each with a distinct aperture size, were used to assess the efficacy of particle filtration in reducing β-CHAs levels in smoked meat. The findings indicated that smoke exposure indeed increases the β-CHAs content of meat. However, only the strainer capable of filtering PM2.5-sized particles reduced the amount of β-CHAs present compared to the control group. In contrast, strainers with larger pore sizes facilitated excessive accumulation of β-CHAs. The presence of aldehydes such as 1 H-pyrrole-2-carboxaldehyde, 5-methylfurfural, benzaldehyde, furfural, and nonanal exhibited a positive correlation with the accumulation of β-CHAs. Conversely, phenolic compounds, including 2-methoxy-4-vinylphenol, 2-methoxy-5-methylphenol, p-cresol, phenol, 2-methoxy-4-(1-propenyl)-, (Z)-, phenol, 3-ethyl-, and phenol, 4-ethyl-2-methoxy-, showed a negative correlation. Thus, filters made from chelated carbonyl trap materials both chemically and physically disrupt the buildup of β-CHAs in smoked meats. The use of this approach will not only improve the quality of these products but will also contribute to decreasing the amount of inhalation pollutants released into the environment.

Systematic metabolic profiling of mice with caerulein-induced acute pancreatitis

Background

Acute pancreatitis (AP) is a complex inflammatory condition with rising incidence globally. Despite various known causes, early diagnosis remains challenging due to limitations in existing biomarkers. Metabolomics offers a promising avenue for identifying novel biomarkers and elucidating underlying pathophysiological mechanisms. Previous AP metabolomics studies primarily focused on analyzing serum, urine, and pancreatic tissues from patients or animal models. However, systematic metabolomics studies that analyze multiple tissues simultaneously are still lacking. The primary aim of our study is to obtain valuable clues to explore the pathophysiological mechanisms of AP and discover novel biomarkers to enable early detection.

Methods

Using a mouse model of AP induced by cerulein, we conducted gas chromatography-mass spectrometry (GC-MS) metabolomic analysis on serum, pancreas, liver, spleen, colon, and kidney samples. Twelve male C57BL/6J mice were randomly divided into AP and control (CON) groups. Serum and tissue samples were collected, processed, and analyzed using established protocols. Multivariate statistical analysis was employed to identify differential metabolites and impacted metabolic pathways.

Results

Distinct metabolic profiles were observed between AP and CON groups across multiple tissues. Elevated levels of ketone bodies, amino acids, citric acid, and lipids were noted, with significant differences in metabolite levels identified. Notably, 3-hydroxybutyric acid (3-HBA), branched-chain amino acids (BCAAs), phenylalanine, and L-lysine showed consistent alterations, suggesting their potential as early diagnostic biomarkers for AP. Pathway analysis revealed perturbations in several metabolic pathways, providing insights into the pathophysiological mechanisms underlying AP.

Conclusions

Our study highlights the utility of metabolomics in identifying potential biomarkers for early diagnosis of AP and elucidating associated metabolic pathways. 3-HBA, BCAAs, phenylalanine and L-lysine emerge as promising biomarkers for further clinical validation. These findings contribute to a better understanding of AP pathophysiology and underscore the potential of metabolomics in precision medicine approaches for AP management.

Effects of Astragaloside IV on Hearing, Inflammatory Factors, and Intestinal Flora in Mice Exposed to Noise

Long-term exposure to noise can cause irreversible hearing loss. Considering that there is no effective drug treatment, it is important to seek preventive treatment for noise-induced hearing loss (NIHL). Although astragaloside IV (AS-IV) protects against NIHL by reducing serum inflammatory factors, there is scarce information on the regulation of inflammatory factors by AS-IV to prevent NIHL. We investigated the hearing thresholds and relationship between the serum levels of inflammatory cytokines and intestinal microbiota of c57bl/6j mice exposed to noise (103 dB SPL 4 h·d-1) for 7 days, treated with or without AS-IV. Our results revealed a lower hearing threshold and lower serum levels of TNF-α, TNF-γ, IL-6, IL-1β, and IFN-γ in the mice treated with AS-IV. Additionally, AS-IV increased the abundance levels of the phylum Firmicutes, class Bacillus, order Lactobacillus, and family Lactobacillus (p < 0.05), and decreased those of the phylum Bacteroidetes and order Bacteroidales (p < 0.05). Lactobacillus and Bacilli negatively correlated with TNF-α, TNF-γ, and IL-1β; Erysipelotrichaceae negatively correlated with INF-γ; and Clostridiales positively correlated with IL-1β. In conclusion, AS-IV reduces the elevation of hearing thresholds in mice, preventing hearing loss in mice exposed to noise, and under the intervention of AS-IV, changes in the levels of inflammatory factors correlate with intestinal flora. We suggest that AS-IV improves intestinal flora and reduces inflammation levels in c57bl/6j mice exposed to noise.

Dietary inulin ameliorates obesity-induced severe acute pancreatitis via gut-pancreas axis

Obesity is a definitive factor of severity and mortality of acute pancreatitis (AP), and gut microbiota dysbiosis is involved in its pathogenesis. However, the effect of gut microbiota modulation by dietary components on high fat diet (HFD)-induced severe AP remains unclear. Here, we found that the inulin, a soluble dietary fiber, mitigated pancreatic injury and systematic inflammation in mice fed HFD, which was dependent on gut microbiota as this protective effect was attenuated in germ-free mice. Inulin treatment suppressed the overgrowth of pathogenic bacteria Escherichia Shigella, Enterococcus, Klebsiella, while increased the abundance of probiotics Akkermansia. Fecal microbiota transplantation from inulin-treated mice to recipient mice reduced pancreatic damage and remodeled intestinal homeostasis. Additionally, inulin increased fecal short chain fatty acids (SCFAs), strengthened gut barrier and restored Paneth cells. The beneficial effect of inulin on improving pancreatic damage and leaky gut was diminished after the suppression of SCFAs. Notably, SCFAs administration, especially butyrate, to HFD mice blocked pancreatic and intestinal injury with the inhibition of histone deacetylase 3 (HDAC3), and pharmacological HDAC3 inhibition mimicked the ameliorative effect of SCFAs. Mechanically, butyrate modulated macrophage M1/M2 polarization balance by suppressing HDAC3 and subsequent acetylation of histone H3K27. Collectively, our data offer new insights into the gut microbiota-pancreas axis that may be leveraged to augment the potential supplementation of prebiotic inulin in the management of obesity associated severe AP.